1. Field of the Invention
The invention relates in general to the field of lifting mechanisms and more particularly to an adapter that engages a threaded rod and is especially useful for creating a hoist or pulley system.
2. Description of the Related Art
Hoists, pulleys, “come alongs,” and the like have been known for centuries as simple mechanisms for exerting mechanical leverage over a lift load. Yet, most improvements to such mechanisms have involved the means for exerting leverage (e.g., a pulley) or the means for attaching the load to be lifted to the line (e.g., a rope) so as to adapt the hoist to lift specialized articles.
Indeed, U.S. Pat. No. 4,619,475 by Sylvest, II discloses an apparatus for lifting drums with a crane or the like. Essentially, the apparatus consists of beam that grasps or clamps onto the annular lips found at the end of oil drum containers so as to provide a safer means for engaging the same.
Campbell (U.S. Pat. No. 5,992,802) discloses a cable support for parallel runs of coaxial cable that is made up of pairs of molded blocks that are stacked on a single threaded rod. The blocks of each pair are identical and have semi-circular cylindrical recesses that cooperate to provide circular, cable-gripping passages. However, Campbell does not teach or suggest providing a hoist or adapter for making a hoist.
Fischer et al. (U.S. Pat. No. 4,455,013) disclose a hoist that has a piston and cylinder combination connected to a slidable sheave set for moving the sheave and an engaged rope. Thus, a load attached to the end of the rope may be lifted. To prevent the rope from rising or falling too quickly, a braking system is engaged if the piston goes above a pre-selected speed limit (thereby, for example, preventing the lifted load from accidentally falling abruptly and causing injury).
In view of the above, it would be desirable to have an adapter that is simple and durable, that can be used with a variety of lines and pulleys, and that can convert a threaded rod into a hoist or pulley system.